Chess Opening Theory/1. Nf3/1...f5/2. e4/2...fxe4

Lisitsin Gambit
Black logically accepted White's gambit and is now attacking White's f3-knight. By far the best move to save it is 3. Ng5. On d4 or e5 it can be kicked by pawns, on h4 it does nothing (as long as Black is wary of a Qh5 check) but on g5 it forces Black to defend her e4-pawn.